The planned start to TEXRail commuter train service linking Fort Worth, North Richland Hills, Grapevine and DFW International Airport originally set for Saturday was called off late Friday afternoon.

Federal Railroad Administration officials in Fort Worth were making final checks Friday. Into the afternoon, Trinity Metro was still expecting the go-ahead, said Paul Ballard, TEXRail's president and chief executive.

"We had a signal issue, identified it, fixed it, and then they said they were going to have to have a conference call," Ballard said. But with his staff on standby and a decision needed, Ballard made the call at 5 p.m. to cancel the planned opening.

"We have been unable to get clearance to operate the entire 27-mile corridor from the Federal Railroad Administration," Trinity Metro announced over social media. "We will announce the new start date as soon as we obtain full clearance from the FRA."

Ballard said at 6:20 p.m. that he still had not heard back from the federal agency. While it has been difficult connecting to a shorthanded Washington, D.C., he said, the delay is not directly related to the government shutdown.

Travelers waited in their seats for a preview trip on Trinity Metro's TEXRail to DFW Airport from the Grapevine/Main Street Station in Grapevine on New Year's Eve.

(Nathan Hunsinger/Staff Photographer)

The final segment awaiting inspection, and the final segment completed, links the former Cotton Belt line from north of downtown Fort Worth to the inner city and its two existing stations — both of which are used in the Trinity Railway Express service to downtown Dallas.

"We're ready to go," Ballard said. "All the conductors are ready. The trains are ready. The one signal problem they observed today is not related to safety. But we will wait as long as it takes for the clearance."

On Monday, the 27-mile commuter line made its maiden voyage from north of downtown, taking some 500 VIPs to a luncheon at the airport. TEXRail plans to make rides free this month.

The billion-dollar investment's impact on the airport was the subject of a planned Monday morning news conference to unveil the station at Terminal B. But that celebration has also been called off because of the uncertainty.

Dallas Area Rapid Transit's DFW Airport Station, on the agency's Orange Line, is currently the site of 900 rail boardings a day. Ridership on TEXRail and DART's Cotton Belt line — once that project comes online in 2022 — is expected to boost the station's numbers to about a million a year.